In an a1200 with an accelerator and a harddrive you would be surfing using aga graphics, which means a max of 256 colours, 16 or so displayed in usable speed, which can make browsing kind of...not so fun, especially considering the low screen modes, so I would advice you to either spend a buckload on a big amiga or use your pc for surfing and your amiga to mess around with for fun. Also amigabrowsers are far from up to date. I did all my surfing on amiga browsers three years ago, but today it is simply impossible (I have not tried IB2.3, btw).
Also you need a monitor (or a tv) capable of displaying pal (15khz) signals if you want any graphical output (you do).
I am not trying to talk you out of it, quite the opposite, I suspect you will have more of a chance of staying if you know what you are getting yourself into, rather than think you have been framed after buying an a1200. For 30 pounds, hell, go for it. If you like what you see, find a cheap accelerator to increase your fun.
Sincerely,
-Kenneth Straarup.